Methods and devices for spinal disc annulus reconstruction and repair

ABSTRACT

The present invention provides methods and devices for annulus disc repair with and without the use of a patch or stent. The methods and devices are particularly suited to the repair and/or reconstruction of the spinal disc wall (annulus) after surgical invasion or pathologic rupture, with reduced failure rate as compared to conventional surgical procedures.

CROSS-REFERENCE TO A RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/327,106, filed Dec. 24, 2002, now U.S. Pat. No. 7,004,970, which is acontinuation-in-part of U.S. patent application Ser. No. 10/133,339,filed Apr. 29, 2002, now U.S. Pat. No. 7,052,516, which claims benefitof U.S. Provisional Application 60/309,105, filed Jul. 31, 2001 and is acontinuation-in-part of U.S. patent application Ser. No. 10/075,615,filed Feb. 15, 2002, which is a continuation-in-part of U.S. patentapplication Ser. No. 09/947,078, filed Sep. 5, 2001, now U.S. Pat. No.6,592,625, which is a continuation of U.S. patent application Ser. No.09/484,706, filed Jan. 18, 2000, now abandoned, which claims the benefitof U.S. Provisional Application No. 60/160,710, filed Oct. 20, 1999.This application is also related to, and claims the benefit of U.S.patent application Ser. No. 10/085,040, filed Mar. 1, 2002.

FIELD OF THE INVENTION

The invention generally relates to methods and implantable medicaldevices for the closure, sealing and/or repair of an aperture in theintervertebral disc annulus. The term “aperture” refers to a hole in theannulus that is a result of a surgical incision into the intervertebraldisc annulus, or the consequence of a naturally occurring tear (rent).The invention generally relates to surgical devices and methods forintervertebral disc wall repair or reconstruction. The invention furtherrelates to an annular repair device, or stent, for annular disc repair.These stents can be of natural or synthetic materials. The effects ofsaid reconstruction is restoration of disc wall integrity and reductionof the failure rate (3-21%) of a common surgical procedure (discfragment removal or discectomy).

BACKGROUND OF THE INVENTION

The spinal column is formed from a number of bony vertebrae, which intheir normal state are separated from each other by intervertebraldiscs. These discs are comprised of the annulus fibrosus, and thenucleus pulposus, both of which are soft tissue. The intervertebral discacts in the spine as a crucial stabilizer, and as a mechanism for forcedistribution between adjacent vertebral bodies. Without the disc,collapse of the intervertebral space occurs, contributing to abnormaljoint mechanics and premature development of arthritic changes.

The normal intervertebral disc has an outer ligamentous ring called theannulus surrounding the nucleus pulposus. The annulus binds the adjacentvertebrae together and is constituted of collagen fibers that areattached to the vertebrae and cross each other so that half of theindividual fibers will tighten as the vertebrae are rotated in eitherdirection, thus resisting twisting or torsional motion. The nucleuspulposus is constituted of loose tissue, having about 85% water content,which moves about during bending from front to back and from side toside.

The aging process contributes to gradual changes in the intervertebraldiscs. The annulus loses much of its flexibility and resilience,becoming more dense and solid in composition. The aging annulus may alsobe marked by the appearance or propagation of cracks or fissures in theannular wall. Similarly, the nucleus desiccates, increasing viscosityand thus losing its fluidity. In combination, these features of the agedintervertebral discs result in less dynamic stress distribution becauseof the more viscous nucleus pulposus, and less ability to withstandlocalized stresses by the annulus fibrosus due to its desiccation, lossof flexibility and the presence of fissures. Fissures can also occur dueto disease or other pathological conditions. Occasionally fissures mayform rents through the annular wall. In these instances, the nucleuspulposus is urged outwardly from the subannular space through a rent,often into the spinal column. Extruded nucleus pulposus can, and oftendoes, mechanically press on the spinal cord or spinal nerve rootlet.This painful condition is clinically referred to as a ruptured orherniated disc.

In the event of annulus rupture, the subannular nucleus pulposusmigrates along the path of least resistance forcing the fissure to openfurther, allowing migration of the nucleus pulposus through the wall ofthe disc, with resultant nerve compression and leakage of chemicals ofinflammation into the space around the adjacent nerve roots supplyingthe extremities, bladder, bowel and genitalia. The usual effect of nervecompression and inflammation is intolerable back or neck pain, radiatinginto the extremities, with accompanying numbness, weakness, and in latestages, paralysis and muscle atrophy, and/or bladder and bowelincontinence. Additionally, injury, disease or other degenerativedisorders may cause one or more of the intervertebral discs to shrink,collapse, deteriorate or become displaced, herniated, or otherwisedamaged and compromised.

Surgical repairs or replacements of displaced or herniated discs areattempted approximately 390,000 times in the USA each year. Until thepresent invention, there was no known way to repair or reconstruct theannulus. Instead, surgical procedures to date are designed to relievesymptoms by removing unwanted disc fragments and relieving nervecompression. While results are currently acceptable, they are notoptimal. Various authors report 3.1-21% recurrent disc herniation,representing a failure of the primary procedure and requiringre-operation for the same condition. An estimated 10% recurrence rateresults in 39,000 re-operations in the United States each year.

An additional method of relieving the symptoms is thermal annuloplasty,involving the heating of sub-annular zones in the non-herniated painfuldisc, seeking pain relief, but making no claim of reconstruction of theruptured, discontinuous annulus wall.

Some have also suggested that the repair of a damaged intervertebraldisc might include the augmentation of the nucleus pulposus, and variousefforts at nucleus pulposus replacement have been reported. The presentinvention is directed at the repair of the annulus, whether or not anuclear augmentation is also warranted.

In addition, there has been experimentation in animals to assess varioussurgical incisions with and without the direct surgical repair of theannulus. These studies were performed on otherwise healthy animals andinvolved no removal or augmentation of nucleus pulposus. The authors ofthese experiments conclude that direct repair of the annulus does notinfluence the healing of the disc.

The present inventors have found, advantageously and contrary toaccepted practice, that the annulus tissue may be sutured and thatannular healing may be facilitated by reapproximation of annular tissue.Methods and devices for carrying out annular repair and/orreconstruction are a subject of the present invention.

BRIEF SUMMARY OF THE INVENTION

The present invention provides methods and related materials forreconstruction of the disc wall in cases of displaced, herniated,ruptured, or otherwise damaged intervertebral discs. In accordance withthe invention, a method is disclosed for intervertebral discreconstruction for treating a disc having an aperture in the wall of theannulus fibrosis, wherein the aperture provides a path for the migrationof nucleus pulposus from the subannular space. The method of theinvention includes, in one embodiment providing an expandable patchhaving a first configuration dimensioned to pass through the apertureand a second expanded configuration having at least one dimension atleast as large as the aperture and having at least one dimension largerthan a corresponding dimension in said first configuration; insertingthe patch through the aperture into the subannular space when the deviceis in the first collapsed configuration; and causing or allowing thepatch to expand in the subannular space into the second expandedconfiguration to bridge the aperture. The method according to theinvention occludes the aperture, helps to prevent the migration ofnucleus pulposus through the aperture, and promotes healing of theaperture through tissue reapproximation.

The objects and various advantages of the invention will be apparentfrom the description which follows. In general, the implantable medicaldevices are placed, positioned, and affixed to the annulus to reducere-extrusion of the nucleus through the aperture by: closing orpartially closing the aperture; restoring the natural integrity of thewall of the annulus; and promoting healing of the annulus through thereapproximation of disc wall tissue. Increased integrity and fasterand/or more thorough healing of the aperture is intended to reducefuture recurrence of herniation of the disc nucleus from theintervertebral disc, and the recurrence of resulting back pain. Inaddition, it is believed that the repair of the aperture could promoteenhanced biomechanics and reduce the possibility of intervertebral discheight collapse and segmental instability, thus resulting in a decreasein the recurrence of back pain after a surgical procedure.

Moreover, the repair of the aperture with the reduction of there-extrusion of the nucleus may also advantageously reduce adhesionformation surrounding the nerve roots. The nuclear material of the discis toxic to the nerves and is believed to cause increased inflammationsurrounding the nerves, which in turn can cause increased scar formation(adhesions or epidural fibrosis) upon healing. Adhesions created aroundthe nerve roots can cause continued back pain. Any reduction in adhesionformation is believed to reduce future recurrence of pain.

The methods and devices of the present inventions may create amechanical barrier to the extrusion of the nucleus from the disc space,add mechanical integrity to the annulus and the tissue surrounding theaperture, and promote faster and more complete healing of the aperture.

Although much of the discussion is directed toward the repair of theintervertebral disc after a surgical procedure, such as discectomy (asurgical procedure performed to remove herniated fragments of the discnucleus), it is contemplated that the devices of the present inventionmay be used in other procedures that involve incisions into the annulusof the intervertebral disc. An example of another procedure that couldrequire a repair technique involves the replacement of the nucleus(nucleus replacement) with an implantable nucleus to replace thefunctioning of the natural nucleus when it is degenerated. The object ofthe invention in this case would be similar in that the repair wouldmaintain the replacement nucleus within the disc space.

According to an embodiment of the invention, a sub-annular patch/stentcan be employed to repair an intervertebral disc annulus. In itssimplest form, the repair of the annulus involves the placement andfixation of a fascial autograft patch to the sub-annular space. Thepatch, when used, can be secured in place with two or more sutures,while re-approximating the tissues surrounding the aperture. Theinvention, through involvement of the sub-annular space and wall for therepair of the aperture has several advantages over the prior art, forexample, sealing the aperture only on the outer surface or sealing theaperture only within the aperture. The first advantage of a repair thatinvolves the sub-annular surface derives itself from the physical natureof a circular (or an elliptical) compressed chamber with a radius, likean intervertebral disc. Sealing the inside wall has the inherentadvantage of being at a smaller radius of curvature versus the outerwall and thus, according to LaPlace's Law, the patch would be subjectedto lower stresses at any given pressure, all else held equal.

Another advantage of utilizing the inner surface to accomplish sealingis that the natural pressure within the disc can enhance the sealing ofthe device against the inner wall of the disc space. Conversely, if therepair is performed on the outer surface of the annulus there is aninherent risk of leakage around the periphery of the device, with theconstant exposure to the pressure of the disc.

Another advantage of the present invention over the prior art inutilizing the inner surface of the annulus is the reduction of the riskof having a portion of the device protruding from the exterior surfaceof the annulus. Device materials protruding from the exterior of theannulus pose a risk of damaging the nerve root and/or spinal canal whichare in close proximity. Damage to these structures can result incontinued pain, incontinence, bowel dysfunction and paralysis.

The present invention incorporates the concept of pulling the tissuestogether that surround the aperture, the inner surface, and the outersurface of the annulus to help close the aperture, increase theintegrity of the repair, and promote healing.

An example of the technique and placement of the device according to oneembodiment of the invention is as follows:

1. An aperture is created measuring approximately, for example, 6 mm×2mm in the wall of the annulus after performing a discectomy procedure inwhich a portion of the nucleus is also removed from the disc space, asshown in FIGS. 32 a, 32 b, 33 a and 33 b.

2. Two or more sutures are passed through the upper and lower surfacesof the aperture and they are pushed within the intervertebral disc spaceto create a “sling” to receive the fascial autograft as shown forexample in FIG. 34.

3. A piece of para-spinal fascial tissue is removed from the patientmeasuring approximately, for example, 10 mm×5 mm.

4. The autograft is folded and compressed to pass through the aperturein the annulus, as shown for example in FIG. 35.

5. The autograft takes a second shape, within the annulus that isuncompressed and oriented to be in proximity of the subannular wall ofthe annulus, within the sling, as shown for example in FIG. 36. Theautograft may be inserted entirely into the subannular space, or aportion may extend into the rent as depicted in FIG. 36.

6. The sutures are tightened, as shown for example in FIG. 37, thustightening the sling surrounding the autograft, to bring the autograftin close proximity with the subannular wall, while providing tension tobring the patch at the subannular surface together with the outersurface of the annular wall, thus creating increased integrity of theannulus surrounding the aperture, as well as causing the autograft totake a second shape that is larger than the aperture. Furthermore, thetightening, and eventual tying of the sutures also promotes there-approximation of the tissue at the outer surface of the annulus andwithin the aperture.

7. The sutures are tied and the ends of the sutures are cut.

8. A piece of autograft fat tissue may be placed over the discectomysite for the prevention of adhesion formation, a typical surgicaltechnique.

9. Standard surgical techniques are utilized to close the access site ofthe surgical procedures.

Several devices according to the present invention can be used topractice the above illustrative inventive steps to seal and/or repairthe intervertebral disc. In each of the representative devices of thisembodiment of the invention, there is: an expandable patch/stent (note:patch, stent and device are used interchangeably) that has, in use, atleast a portion of the device in proximity to the sub-annular space ofthe intervertebral disc annulus; a means to affix the patch to stay inproximity with the annulus; a means to draw the patch and the annulartissue together and fasten in tension; and a means to help reduce therelative motion of the surfaces of the aperture after fixation, and thuspromote healing. According to one feature and object of the presentinvention, close approximation of tissue, while reducing the motion ofthe surfaces, provides the optimal environment for healing.

The concepts disclosed hereinbelow accomplish these objectives, as wellas advantageously additionally incorporating design elements to reducethe number of steps (and time), and/or simplify the surgical technique,and/or reduce the risk of causing complications during the repair of theintervertebral disc annulus. In addition, the following devices maybecome incorporated by the surrounding tissues, or to act as a scaffoldin the short-term (3-6 months) for tissue incorporation.

In an exemplary embodiment, one or more mild biodegradable surgicalsutures can be placed at about equal distances along the sides of apathologic aperture in the ruptured disc wall (annulus) or along thesides of a surgical incision in the annular wall, which may be weakenedor thinned.

Sutures are then tied in such fashion as to draw together the sides ofthe aperture, effecting reapproximation or closure of the opening, toenhance natural healing and subsequent reconstruction by natural tissue(fibroblasts) crossing the now surgically narrowed gap in the discannulus.

A 25-30% reduction in the rate of recurrence of disc nucleus herniationthrough this aperture has been achieved using this method.

In another exemplary embodiment, the method can be augmented by creatinga subannular barrier in and across the aperture by placement of a patchof human muscle fascia (muscle connective tissue) or any otherautograft, allograft, or xenograft acting as a bridge or a scaffold,providing a platform for traverse of fibroblasts or other normal cellsof repair existing in and around the various layers of the disc annulus,prior to closure of the aperture.

A 30-50% reduction in the rate of recurrence of disc herniation has beenachieved using the aforementioned fascial augmentation with thisembodiment.

Having demonstrated that human muscle fascia is adaptable for annularreconstruction, other biocompatible membranes can be employed as abridge, stent, patch or barrier to subsequent migration of the discnucleus through the aperture. Such biocompatible materials may be, forexample, medical grade biocompatible fabrics, biodegradable polymericsheets, or form fitting or non-form fitting fillers for the cavitycreated by removal of a portion of the disc nucleus pulposus in thecourse of the disc fragment removal or discectomy. The prostheticmaterial can be placed in and around the intervertebral space, createdby removal of the degenerated disc fragments.

In some clinical instances, for instance, where a wall of an annuluscontains a sufficiently small aperture, or where a wall of the annulusis weakened or thin, the present invention may be advantageouslyaccomplished without the use of a patch. Thus, in another embodiment,the present invention also includes a method of repairing orreconstructing an annulus comprising placing at least one fixationdevice into, or through, the wall of an annulus surrounding the aperture(or weakened or thin portion of the annulus) and causing, or allowing,the devices to be drawn in tension thereby pulling together, wholly orpartially, the tissues surrounding annular tissue. Devices for use withthe method are also disclosed. The inventive method forms a mechanicalbarrier, or partial mechanical barrier, to the migration of nucleuspulposus and/or helps to promote healing of the aperture through tissuereapproximation.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate illustrative embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 shows a perspective view of an illustrative embodiment of anannulus stent.

FIG. 2 shows a front view of the annulus stent of FIG. 1.

FIG. 3 shows a side view of the annulus stent of FIG. 1.

FIGS. 4A-4C show a front view of alternative illustrative embodiments ofan annulus stent.

FIGS. 5A-5B show the alternative embodiment of a further illustrativeembodiment of an annulus stent.

FIGS. 6A-6B show the alternative embodiment of a further illustrativeembodiment of an annulus stent.

FIG. 7 shows a primary closure of an opening in the disc annulus.

FIGS. 8A-8B show a primary closure with a stent.

FIG. 9 shows a method of suturing an annulus stent into the disc annulusutilizing fixation points on vertebral bodies.

FIGS. 10A-10B show a further illustrative embodiment of an annulus stentwith flexible bladder being expanded into the disc annulus.

FIGS. 11A-11D show an annulus stent being inserted into and expandedwithin the disc annulus.

FIGS. 12A-12B show an annulus stent with a flexible bladder beingexpanded.

FIG. 13 shows a perspective view of a further illustrative embodiment ofan annulus stent.

FIG. 14 shows a first collapsed view of the annulus stent of FIG. 13.

FIG. 15 shows a second collapsed view of the annulus stent of FIG. 13.

FIGS. 16A-16C show the annulus stent of FIG. 13 being inserted into thedisc annulus.

FIGS. 17A-17C show a method of inserting the annulus stent of FIG. 13into the disc annulus.

FIGS. 18A-18B show a further illustrative embodiment of an annulus stentwith a flexible bladder.

FIGS. 19A-19B show another illustrative embodiment of an annulus stentwith a flexible bladder.

FIG. 20 shows an expanded annulus stent with barbs on the radialextension.

FIG. 21 shows a still further illustrative embodiment of an annulusstent with a compressible core.

FIG. 22 shows a still further illustrative embodiment of an introductiondevice for an annulus stent.

FIG. 23 shows a modification of the device depicted in FIG. 22.

FIG. 24 shows an exemplary introduction tool for use with the devices ofFIGS. 22 and 23 with a stent deflected proximally.

FIG. 25 shows an exemplary introduction tool for use with the devices ofFIGS. 22 and 23 with a stent deflected distally.

FIG. 26 shows an exemplary introduction tool for use with the devices ofFIGS. 22 and 23 with a stent deflected partially distally and partiallyproximally.

FIG. 27 shows a still further illustrative embodiment of a stent devicehaving a grasping feature and fixation devices in the form of barbs.

FIG. 28 shows the illustrative embodiment in FIG. 27 deployedsubannularly.

FIG. 29 shows a still further illustrative embodiment of an annulusstent employing a secondary barbed fixation device.

FIG. 30 shows a still further illustrative embodiment of an annulusstent employing another example of a secondary barbed fixation device.

FIG. 31 shows the frame of a still further illustrative embodiment of anannulus stent having a metal substrate being machined from flat stock.

FIG. 32 a shows a herniated disc in perspective view, and FIG. 32 bshows the same disc after discectomy.

FIG. 33 a shows a top view of the disc post-discectomy, and FIG. 33 bshows a posteriolateral view of the disk showing an incision.

FIG. 34 shows schematically the creation of a subannular sling usingsutures.

FIG. 35 schematically shows the introduction of a compressed autograftstent/patch into the subannular space.

FIG. 36 schematically shows the autograft of FIG. 35 in an expandedshape within the annulus.

FIG. 37 schematically shows the tightening of the sutures toreappoximate the annulus aperture and draw the stent/patch of FIG. 35toward the annular wall.

FIG. 38 shows an exemplary collar for use in repairing a disc annulus.

FIG. 39 schematically depicts the collar of FIG. 38 in use for discannulus repair.

FIG. 40 shows a still further exemplary embodiment of the presentinvention using a bag to contain the patch/stent.

FIG. 41 a-e show still further illustrative embodiments of the presentinvention having frames.

FIG. 42 shows an illustrative method for placing a barbed expandablepatch in the subannular disc space.

FIG. 43 shows the patch of FIG. 42 being fixed to the inside wall of theannulus fibrosus.

FIGS. 44 a-g show a still further illustrative embodiment of anintroduced and expanded annulus stent/patch being fixated and theaperture reapproximated.

FIGS. 45 a-c schematically depict a still further embodiment of thepresent invention where an expandable stent/patch is tethered in situusing a cinch line.

FIGS. 46 a-c schematically depict the cinch line of FIG. 45 beingfixated through use of a surgical staple device.

FIGS. 47 a-b show an illustrative embodiment of a suturing arrangementfor securing a patch/stent in the annulus.

FIG. 48 a-b depict a still further illustrative embodiment wherefixation sutures are placed into the vertebral body or the Sharpeyfibers.

FIGS. 49 a-c schematically depict a still further embodiment of thepresent invention where an expandable stent/patch is tethered in situusing a cinch line.

FIGS. 50 a-c schematically depict the cinch line of FIG. 49 beingfixated through use of a barbed surgical staple device that penetratesthe patch/stent.

FIG. 51 depicts an exemplary use of filler tissue within the apertureduring placement of a patch/stent tethered by a cinch line.

FIGS. 52 a-e shows exemplary embodiments of various additionalpatch/stent fixation techniques.

FIG. 53 shows a still further illustrative embodiment of a stent/patchhaving a frame.

FIG. 54 a-f shows a still further illustrative embodiment of an annularstent/patch having a self-contained fixation tightening feature.

FIG. 55 shows a still further exemplary embodiment of the presentinvention having external fixation anchors.

FIG. 56 a-c shows a still further exemplary embodiment of the presentinvention having external fixation anchors.

FIG. 57 a-c shows a still further exemplary embodiment of the presentinvention having external fixation anchors.

FIG. 58 a-c shows a still further exemplary embodiment of the presentinvention having external fixation anchors.

FIG. 59 shows a still further exemplary embodiment of the presentinvention having a springing arrangement.

FIG. 60 shows a delivered configuration of fixation means that mayresult from the use of a single device to deliver multiple barbs orT-anchors sequentially or simultaneously.

FIGS. 61 a-b show a suitable configuration of an anchor band deliverydevice.

FIG. 62 a shows an anchor band delivery device comprising two deuice,each with at least one T-anchor (bards) and band with pre-tied knot andoptional knot pusher.

FIG. 62 b shows the anchor band delivery device of FIG. 62 a with bardsdeployed.

FIG. 62 c shows the fixation device of FIG. 62 a-b in place and optionalknot pusher.

FIG. 62 d shows annular tissues reapproximated with a fixation deviceaccording to an embodiment of the invention.

FIG. 63 shows an anchor and band delivery device according to oneembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to selected illustrativeembodiments of the invention, with occasional reference to theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

In one embodiment of the present invention, as shown in FIG. 7, adamaged annulus 42 is repaired by use of surgical sutures 40. One ormore surgical sutures 40 are placed at about equal distances along thesides of a pathologic aperture 44 in the annulus 42. Reapproximation orclosure of the aperture 44 is accomplished by tying the sutures 40 sothat the sides of the aperture 44 are drawn together. Thereapproximation or closure of the aperture 44 enhances the naturalhealing and subsequent reconstruction by the natural tissue (e.g.,fibroblasts) crossing the now surgically narrowed gap in the annulus 42.Preferably, the surgical sutures 40 are biodegradable, but permanentnon-biodegradable may be utilized. In all embodiments wherebiodegradable materials are indicated, suitable biodegradable materialsmay include, but are not limited to, biodegradable polyglycolic acid,swine submucosal intestine, collagen, or polylactic acid. Other suitablesuturing (and band) materials include, e.g., polymeric materials such asPET, polyester (e.g., Dacron™), polypropylene, and polyethylene.

Additionally, to repair a weakened or thinned wall of a disc annulus 42,a surgical incision can be made along the weakened or thinned region ofthe annulus 42 and one or more surgical sutures 40 can be placed atabout equal distances laterally from the incision. Reapproximation orclosure of the incision is accomplished by tying the sutures 40 so thatthe sides of the incision are drawn together. The reapproximation orclosure of the incision enhances the natural healing and subsequentreconstruction by the natural tissue crossing the now surgicallynarrowed gap in the annulus 42. Preferably, the surgical sutures 40 arebiodegradable, but permanent non-biodegradable materials may beutilized.

Where necessary or desirable, the method can be augmented by placing apatch of human muscle fascia or any other autograft, allograft orxenograft in and across the aperture 44. The patch acts as a bridge inand across the aperture 44, providing a platform for traverse offibroblasts or other normal cells of repair existing in and around thevarious layers of the disc annulus 42, prior to closure of the aperture44. FIGS. 8A-B, for example, show a biocompatible membrane employed asan annulus stent 10, being placed in and across the aperture 44. Theannulus stent 10 acts as a bridge in and across the aperture 44,providing a platform for a traverse of fibroblasts or other normal cellsof repair existing in and around the various layers of the disc annulus42, prior to closure of the aperture 44. In some embodiments the device,stent or patch can act as a scaffold to assist in tissue growth thathealingly scars the annulus.

In an illustrative embodiment, as shown in FIGS. 1-3, the annulus stent10 comprises a centralized vertical extension 12, with an upper section14 and a lower section 16. The centralized vertical extension 12 can betrapezoid in shape through the width and may be from about 8 mm-12 mm inlength.

Additionally, the upper section 14 of the centralized vertical extension12 may be any number of different shapes, as shown in FIGS. 4A through4C, with the sides of the upper section 14 being curved or with theupper section 14 being circular in shape. Furthermore, the annulus stent10 may contain a recess between the upper section 14 and the lowersection 16, enabling the annulus stent 10 to form a compatible fit withthe edges of the aperture 44.

The upper section 14 of the centralized vertical extension 12 cancomprise a slot 18, where the slot 18 forms an orifice through the uppersection 14. The slot 18 is positioned within the upper section 14 suchthat it traverses the upper section's 14 longitudinal axis. The slot 18is of such a size and shape that sutures, tension bands, staples or anyother type of fixation device known in the art may be passed through, toaffix the annulus stent 10 to the disc annulus 42.

In an alternative embodiment, the upper section 14 of the centralizedvertical extension 12 may be perforated. The perforated upper section 14contains a plurality of holes that traverse the longitudinal axis ofupper section 14. The perforations are of such a size and shape thatsutures, tension bands, staples or any other type of fixation deviceknown in the art may be passed through, to affix the annulus stent 10 tothe disc annulus 42.

The lower section 16 of the centralized vertical extension 12 cancomprise a pair of lateral extensions, a left lateral extension 20 and aright lateral extension 22. The lateral extensions 20 and 22 comprise aninside edge 24, an outside edge 26, an upper surface 28, and a lowersurface 30. The lateral extensions 20 and 22 can have an essentiallyconstant thickness throughout. The inside edge 24 is attached to and isabout the same length as the lower section 16. The outside edge 26 canbe about 8 mm-16 mm in length. The inside edge 24 and the lower section16 meet to form a horizontal plane, essentially perpendicular to thecentralized vertical extension 12. The upper surface 28 of the lateralextensions 20 and 22 can form an angle from about 0°-60° below thehorizontal plane. The width of the annulus stent 10 may be from about 3mm-8 mm.

Additionally, the upper surface 28 of the lateral extensions 20 and 22may be barbed for fixation to the inside surface of the disc annulus 42and to resist expulsion through the aperture 44.

In an alternative embodiment, as shown in FIG. 4B, the lateralextensions 20 and 22 have a greater thickness at the inside edge 24 thanat the outside edge 26.

In an illustrative embodiment, the annulus stent 10 is a solid unit,formed from one or more of the flexible resilient biocompatible orbioresorbable materials well know in the art. The selection ofappropriate stent materials may be partially predicated on specificstent construction and the relative properties of the material suchthat, after fixed placement of the stent, the repair may act to enhancethe healing process at the aperture by relatively stabilizing the tissueand reducing movement of the tissue surrounding the aperture.

For example, the annulus stent 10 may be made from:

A porous matrix or mesh of biocompatible and bioresorbable fibers actingas a scaffold to regenerate disc tissue and replace annulus fibrosus asdisclosed in, for example, U.S. Pat. No. 5,108,438 (Stone) and U.S. Pat.No. 5,258,043 (Stone), a strong network of inert fibers intermingledwith a bioresorbable (or bioabsorable) material which attracts tissueingrowth as disclosed in, for example, U.S. Pat. No. 4,904,260 (Ray etal.).

a biodegradable substrate as disclosed in, for example, U.S. Pat. No.5,964,807 (Gan at al.); or

an expandable polytetrafluoroethylene (ePTFE), as used for conventionalvascular grafts, such as those sold by W.L. Gore and Associates, Inc.under the trademarks GORE-TEX and PRECLUDE, or by Impra, Inc. under thetrademark IMPRA.

Furthermore, the annulus, stent 10, may contain hygroscopic material fora controlled limited expansion of the annulus stent 10 to fill theevacuated disc space cavity.

Additionally, the annulus stent 10 may comprise materials to facilitateregeneration of disc tissue, such as bioactive silica-based materialsthat assist in regeneration of disc tissue as disclosed in U.S. Pat. No.5,849,331 (Ducheyne, et al.), or other tissue growth factors well knownin the art.

Many of the materials disclosed and described above representembodiments where the device actively promotes the healing process. Itis also possible that the selection of alternative materials ortreatments may modulate the role in the healing process, and thuspromote or prevent healing as may be required. It is also contemplatedthat these modulating factors could be applied to material substrates ofthe device as a coating, or similar covering, to evoke a differenttissue response than the substrate without the coating.

In further embodiments, as shown in FIGS. 5AB-6AB, the left and rightlateral extensions 20 and 22 join to form a solid pyramid or cone.Additionally, the left and right lateral extensions 20 and 22 may form asolid trapezoid, wedge, or bullet shape. The solid formation may be asolid biocompatible or bioresorbable flexible material, allowing thelateral extensions 20 and 22 to be compressed for insertion intoaperture 44, then to expand conforming to the shape of the annulus' 42inner wall.

Alternatively, a compressible core may be attached to the lower surface30 of the lateral extensions 20 and 22, forming a pyramid, cone,trapezoid, wedge, or bullet shape. The compressible core may be madefrom one of the biocompatible or bioresorbable resilient foams wellknown in the art. The core can also comprise a fluid-expandablemembrane, e.g., a balloon. The compressible core allows the lateralextensions 20 and 22 to be compressed for insertion into aperture 44,then to expand conforming to the shape of the annulus' 42 inner wall andto the cavity created by pathologic extrusion or surgical removal of thedisc fragment.

In an illustrative method of use, as shown in FIGS. 11A-D, the lateralextensions 20 and 22 are compressed together for insertion into theaperture 44 of the disc annulus 42. The annulus stent 10 is theninserted into the aperture 44, where the lateral extensions 20, 22expand. In an expanded configuration, the upper surface 28 cansubstantially conform to the contour of the inside surface of the discannulus 42. The upper section 14 is positioned within the aperture 44 sothat the annulus stent 10 may be secured to the disc annulus 42, usingmeans well known in the art.

In an alternative method, where the length of the aperture 44 is lessthan the length of the outside edge 26 of the annulus stent 10, theannulus stent 10 can be inserted laterally into the aperture 44. Thelateral extensions 20 and 22 are compressed, and the annulus stent 10can then be laterally inserted into the aperture 44. The annulus stent10 can then be rotated inside the disc annulus 42, such that the uppersection 14 can be held back through the aperture 44. The lateralextensions 20 and 22 are then allowed to expand, with the upper surface28 contouring to the inside surface of the disc annulus 42. The uppersection 14 can be positioned within, or proximate to, the aperture 44 inthe subannular space such that the annulus stent 10 may be secured tothe disc annulus, using means well known in the art.

In an alternative method of securing the annulus stent 10 in theaperture 44, as shown in FIG. 9, a first surgical screw 50 and secondsurgical screw 52, with eyeholes 53 located at the top of the screws 50and 52, are inserted into the vertebral bodies, illustratively depictedas adjacent vertebrae 54 and 56. After insertion of the annulus stent 10into the aperture 44, a suture 40 is passed down though the disc annulus42, adjacent to the aperture 44, through the eye hole 53 on the firstscrew 50 then back up through the disc annulus 42 and through theorifice 18 on the annulus stent 10. This is repeated for the secondscrew 52, after which the suture 40 is secured. One or more surgicalsutures 40 are placed at about equal distances along the sides of theaperture 44 in the disc annulus 42. Reapproximation or closure of theaperture 44 is accomplished by tying the sutures 40 in such a fashionthat the sides of the aperture 44 are drawn together. Thereapproximation or closure of the aperture 44 enhances the naturalhealing and subsequent reconstruction by the natural tissue crossing thenow surgically narrowed gap in the annulus 42. Preferably, the surgicalsutures 40 are biodegradable but permanent non-biodegradable forms maybe utilized. This method should decrease the strain on the disc annulus42 adjacent to the aperture 44, precluding the tearing of the suturesthrough the disc annulus 42.

It is anticipated that fibroblasts will engage the fibers of the polymeror fabric of the intervertebral disc stent 10, forming a strong wallduplicating the currently existing condition of healing seen in thenormal reparative process.

In an additional embodiment, as shown in FIGS. 10A-B, a flexible bladder60 is attached to the lower surface 30 of the annulus stent 10. Theflexible bladder 60 comprises an internal cavity 62 surrounded by amembrane 64, where the membrane 64 is made from a thin flexiblebiocompatible material. The flexible bladder 60 is attached to the lowersurface 30 of the annulus stent 10 in an unexpanded condition. Theflexible bladder 60 is expanded by injecting a biocompatible fluid orexpansive foam, as known in the art, into the internal cavity 62. Theexact size of the flexible bladder 60 can be varied for differentindividuals. The typical size of an adult nucleus is about 2 cm in thesemi-minor axis, 4 cm in the semi-major axis, and 1.2 cm in thickness.

In an alternative embodiment, the membrane 64 is made of asemi-permeable biocompatible material. The mechanical properties of theinjectate material may influence the performance of the repair and it iscontemplated that materials which are “softer” or more compliant as wellas materials that are less soft and less compliant than healthy nucleusare contemplated within the scope of certain embodiments of theinvention. It must be understood that in certain embodiments the volumeadded to the subannular space may be less than equal to or larger thanthe nucleus volume removed. The volume of the implant may vary over timeas well in certain embodiments.

In an illustrative embodiment, a hydrogel is injected into the internalcavity 62 of the flexible bladder 60. A hydrogel is a substance formedwhen an organic polymer (natural or synthetic) is cross-linked via,covalent, ionic, or hydrogen bonds to create a three-dimensionalopen-lattice structure, which entraps water molecules to form a gel. Thehydrogel may be used in either the hydrated or dehydrated form.

In a method of use, where the annulus stent 10 has been inserted intothe aperture 44, as has been previously described and shown in FIGS. 12A-B, an injection instrument, as known in the art, such as a syringe, isused to inject the biocompatible fluid or expansive foam into theinternal cavity 62 of the flexible bladder 60. The biocompatible fluidor expansive foam is injected through the annulus stent 10 into theinternal cavity 62 of the flexible bladder 60. Sufficient material isinjected into the internal cavity 62 to expand the flexible bladder 60to fill the void in the intervertebral disc cavity. The use of theflexible bladder 60 is particularly useful when it is required to removeall or part of the intervertebral disc nucleus.

The surgical repair of an intervertebral disc may require the removal ofthe entire disc nucleus, being replaced with an implant, or the removalof a portion of the disc nucleus thereby leaving a void in theintervertebral disc cavity. The flexible bladder 60 allows for theremoval of only the damaged section of the disc nucleus, with theexpanded flexible bladder 60 filling the resultant void in theintervertebral disc cavity. A major advantage of the annulus stent 10with the flexible bladder 60 is that the incision area in the annulus 42can be reduced in size, as there is no need for the insertion of animplant into the intervertebral disc cavity.

In an alternative method of use, a dehydrated hydrogel is injected intothe internal cavity 62 of the flexible bladder 60. Fluid, from the discnucleus, passes through the semipermeable membrane 64 hydrating thedehydrated hydrogel. As the hydrogel absorbs the fluid the flexiblebladder 60 expands, filling the void in the intervertebral disc cavity.

In an alternative embodiment, as shown in FIG. 13, the annulus stent 10is substantially umbrella shaped, having a central hub 66 with radiallyextending struts 67. Each of the struts 67 is joined to the adjacentstruts 67 by a webbing material 65, forming a radial extension 76 aboutthe central hub 66. The radial extension 76 has an upper surface 68 anda lower surface 70, where the upper surface 68 contours to the shape ofthe disc annulus' 42 inner wall when inserted as shown in FIG. 17A-C,and where the lower surface 70 contours to the shape of the discannulus' 42 inner wall when inserted as shown in FIG. 16A-C. The radialextension 76 may be substantially circular, elliptical, or rectangularin plan shape. Additionally, as shown in FIG. 20, the upper surface 68of the radial extension 76 may be barbed 82 for fixation to the discannulus' 42 inner wall and to resist expulsion through the aperture 42.

As shown in FIGS. 14 and 15, the struts 67 are formed from flexiblematerial, allowing the radial extension 76 to be collapsed for insertioninto aperture 44, then the expand conforming to the shape of the innerwall of disc annulus 42. In the collapsed position, the annulus stent 10is substantially frustoconical or shuttlecock shaped, and having a firstend 72, comprising the central hub 66, and a second end 74.

In an alternative embodiment, the radial extension 76 has a greaterthickness at the central hub 66 edge than at the outside edge.

In an embodiment, the annulus stent 10 is a solid unit, formed from oneor more of the flexible resilient biocompatible or bioresorbablematerials well known in the art.

Additionally, the annulus stent 10 may comprise materials to facilitateregeneration of disc tissue, such as bioactive silica based materialsthat assist in regeneration of disc tissue as disclosed in U.S. Pat. No.5,849,331 (Ducheyne, et al.), or other tissue growth factors well knownin the art.

Alternatively, as shown in FIG. 21, a compressible core 84 may beattached to the lower surface 70 of the radial extension 76. Thecompressible core 84 may be made from one of the biocompatible orbioresorbable resilient foams well known in the art. The compressiblecore 84 allows the radial extension 76 to be compressed for insertioninto aperture 44 then to expand conforming to the shape of the discannulus' 42 inner wall and to the cavity created by pathologic extrusionor surgical removal of the disc fragment.

In an additional embodiment, as shown in FIGS. 18A and 18B, a flexiblebladder 80 is attached to the lower surface 70 of the annulus stent 10.The flexible bladder 80 comprises an internal cavity 86 surrounded by amembrane 88, where the membrane 88 is made from a thin flexiblebiocompatible material. The flexible bladder 86 is attached to the lowersurface 70 of the annulus stent 10 in an unexpanded condition. Theflexible bladder 80 is expanded by injecting a biocompatible fluid orexpansive foam, as known in the art, into the internal cavity 86. Theexact size of the flexible bladder 80 can be varied for differentindividuals. The typical size of an adult nucleus is 2 cm in thesemi-minor axis, 4 cm in the semi-major axis and 1.2 cm in thickness.

In an alternative embodiment, the membrane 88 is made of asemi-permeable biocompatible material.

In a method of use, as shown in FIGS. 16A-16C, the radial extension 76is collapsed together, for insertion into the aperture 44 of the discannulus 42. The radial extension 76 is folded such the upper surface 68forms the outer surface of the cylinder. The annulus stent 10 is theninserted into the aperture 44, inserting the leading end 72 though theaperture 44 until the entire annulus stent 10 is within the disc annulus42. The radial extension 76 is released, expanding within the disc 44.The lower surface 70 of the annulus stent 10 contours to the inner wallof disc annulus 42. The central hub 66 is positioned within the aperture44 so that the annulus stent 10 may be secured to the disc annulus 42using means well known in the art.

It is anticipated that fibroblasts will engage the fibers of the polymerof fabric of the annulus stent 10, forming a strong wall duplicating thecurrently existing condition of healing seen in the normal reparativeprocess.

In an alternative method of use, as shown in FIGS. 17A-17C, the radialextension 76 is collapsed together for insertion into the aperture 44 ofthe disc annulus 42. The radial extension 76 is folded such that theupper surface 68 forms the outer surface of the stent, for example in afrustoconical configuration as illustrated. The annulus stent 10 is theninserted into the aperture 44, inserting the tail end 74 through theaperture 44 until the entire annulus stent 10 is in the disc. The radialextension 76 is released, expanding within the disc. The upper surface68 of the annulus stent 10 contours to the disc annulus' 42 inner wall.The central hub 66 is positioned within the aperture 44 so that theannulus stent 10 may be secured to the disc annulus 42, using means wellknown in the art.

In one illustrative embodiment, the barbs 82 on the upper surface 68 ofone or more strut 67 or other feature of the radial extension 76, engagethe disc annulus' 42 inner wall, holding the annulus stent 10 inposition.

In a method of use, as shown in FIGS. 12A-12B, where the annulus stent10 has been inserted into the aperture 44, as has been previouslydescribed. Similarly, for the stent shown in FIGS. 18 through 21, aninjection instrument, as known in the art, such as a syringe, can beused to inject the biocompatible fluid or expansive foam into theinternal cavity 86 of the flexible bladder 80. The biocompatible fluidor expansive foam is injected through the annulus stent 10 into theinternal cavity 86 of the flexible bladder 80. Sufficient material isinjected into the internal cavity 86 to expand the flexible bladder 80to fill the void in the intervertebral disc cavity. The material can becurable (i.e., glue). The use of the flexible bladder 80 is particularlyuseful when it is required to remove all or part of the intervertebraldisc nucleus.

It should be noted that in any of the “bag” embodiments described hereinone wall or barrier can be made stiffer and less resilient than others.This relatively stiff wall member can then be placed proximate theannulus wall and can advantageously promote, in addition to itsreparative properties, bag containment within the annulus.

FIG. 22 shows a further aspect of the present invention. According to afurther illustrative embodiment, a simplified schematic cross section ofa vertebral pair is depicted including an upper vertebral body 110, alower vertebral body 112 and an intervertebral disc 114. An aperture orrent 116 in the annulus fibrosus (AF) is approached by a tube 118, whichis used to deliver a device 120 according to a further aspect of thepresent invention. The device 120 may be captured by a delivery tool 122through the use of a ring or other fixation feature 124 mounted on therepair device 120.

FIG. 23 shows a delivery method similar to that depicted in FIG. 22,with the exception that the tube 118A has a reduced diameter so that itmay enter into the sub-annular space of the disc 114 through theaperture or rent.

Turning to FIG. 25, according to a further aspect of the presentinvention, the delivery of the device 120 through the delivery tube 118or 118A may be facilitated by folding the arms or lateral extensions128, 130 of the device to fit within the lumen of the tube 118 or 118Aso that the stent or device 120 is introduced in a collapsedconfiguration. The device 120 is moved through the lumen of the tubes118 or 118A through the use of delivery tool 122. FIG. 25 shows the armsdeflected in a distal, or forward direction for insertion into thedelivery tube 118 or 118A while FIG. 24 shows the arms 128, 130deflected into a proximal position. FIG. 26 shows the device 120 curledso that one arm 128 is projecting distally, or in a forward direction,and the other arm 130 is projecting proximally, or in a rearwarddirection. Because the lateral extent of the device is relativelyflexible, whether the device is of natural or synthetic material, othercollapsible configurations consistent with the intent of this inventionare also possible, including twisting, balling, crushing, etc.

FIG. 27 shows the device 120 having a series of peripheral barbstructures typified by barb 132 located at the edges. In operation,these barbs may be forced into the annulus fibrosus as seen inconnection with FIG. 28. Barb placement can be anywhere on the device120 provided that at least some number of barbs are likely to findannulus fibrosus tissue to anchor in during placement. For a simpleaperture or rent, placement on the periphery of the device body is areasonable choice, but for complex tears, it may be desirable to place aplurality of barbs on the device not knowing in advance which barbs willfind tissue to anchor in during placement.

FIG. 29 shows an alternative fixation strategy where a pair of barbs 134and 136 are plunged into the annulus fibrosus from the exterior of theannulus while the device 120 is retained in the sub-annular space bymeans of a tether 142. Although there are a wide variety of fixationdevices in this particular example, a tether 142 may be knotted 145 withthe band 144 holding the barbs 134 and 136 together to fix the device inthe sub-annular space. The knot is shown in an uncinched position toclarify the relationship between the tether 142 and the band 144. Usingthis approach, the device can be maintained in a subannular position bythe barbed bands while the tether knot is cinched, advantageouslysimultaneously reapproximating the annulus to close the aperture whiledrawing the device into sealing, bridging engagement with the subannularwall of the annulus fibrosus.

FIG. 30 shows an alternative fixation strategy where the barbs 148 and150 are sufficiently long that they can pierce the body of the device120 and extend all the way through the annulus fibrosus into the device120. In this configuration, the band 144 connecting the barbs 148 and150 may be tightened to gently restrain and position the device 120 inthe sub-annular space, or tightened with greater force to reapproximatethe aperture or rent.

FIG. 31 shows a still further illustrative embodiment according toanother aspect of the present invention. In this embodiment, a metalsubstrate 160 is incorporated into the device 120. This piece can bemachined from flat stock and includes the loop 162 as well as barbstypified by barb 164. When formed in to the device 120 the structureshown in FIG. 31 is used in a manner analogous to FIG. 27 and FIG. 28.

Stents can expand to be planar, for example as shown hereinabove inFIGS. 4, 8, 9, 11 and 12, or they can expand to be three-dimensional asshown hereinabove in FIGS. 5 and 10. FIGS. 34-36 depict a further threedimensional patch/stent using an autograft formed of fascial tissue.FIG. 34 shows the superior vertebral body 202 and the inferior vertebralbody 204 surrounding a disc having an annulus fibrosus 206 and nucleuspulposus 203 in the subannular space. According to this illustrativeembodiment of the invention, a suture 210 is passed from outside theannulus through the wall of the annulus on one side of an aperture 208and into the subannular space as shown. The suture is then passed backout through the annular wall on an opposing side of the aperture 208leaving a loop or sling 212 of suture in the subannular space. As shownin the posterior view on the right side of FIG. 34, more than one suturecan be applied. Turning to FIG. 35, a fascial autograft 214 is theninserted through the aperture 208 into the subannular space using, forexample, forceps 216. FIG. 36 shows the fascial stent/patch 214 fullyinserted into the subannular space within the suture sling 212. Theclosure of the aperture is accomplished simultaneously with pulling theautograft 214 toward the annular wall as shown in FIG. 37. The suture210 can be cinched 218 or tied to maintain the closure and the fixationof the patch/stent.

Patches can be folded and expanded in a single plane or in threedimensions. As shown in FIGS. 24-25 and 41 for example, collapsing thepatch can be accomplished laterally, whether the device is a singlematerial or composite. Other embodiments, such as that shown in FIG. 1can collapse vertically, and still others such as that shown in FIG. 26,longitudinally. Others can collapse in three dimensions, such as thoseshown in FIGS. 13-15 and 36. Devices which expand in three dimensionscan be packaged in a restraining jacket, such as a gelatine shell or“gelcap” for example, or a mesh of biosorbable or dissolvable material,that would allow for facile placement and subsequent expansion.

Patches can also be constructed of a single component, as shown forexample in FIG. 36, made of autograft or a synthetic material such asDacron, or for example where the stent is a gelcap. They can be made ofmultiple components. An exemplary stent (not shown) can be made from apolymeric material, for example silicone rubber, which can be formed tohave a natural unstressed shape, for example that of a “Bulb”. A styletor push-rod can, for example, be inserted on the inside of the bulb tostretch the bulb into a second shape which is thinner and elongated. Thesecond shape is sufficient to place within the aperture in the annulus.Upon placement of the device within the sub-annular space, the push-rodis removed and the bulb assumes it natural, unstressed state, assuming alarger dimension within the sub-annular space. Although silicone is usedin this example, other metallic constructs could also be envisioned suchas a Nitinol braided device that has a natural unstressed shape andassumes a second shape under tension for the delivery of the device. Itis also contemplated that the opposite scenario can also accomplish thesimilar objective. In this alternative embodiment, the device can have afirst configuration that is unstressed and elongated and assumes asecond, larger configuration (bulb) under stress. In this embodiment, aportion of the stylet or rod that is used to mechanically activate thedevice would be left behind to hold the expansion element in itsstressed configuration.

Multiple components could include a frame to help with expansion of thedevice and a covering to obtain biocompatibility and tissue ingrowth.Examples of different frame configurations might include an expandable“Butterfly” or “Figure-8” configuration that could be constructed ofwire material, such as Nitinol or multiple wires. Exemplary embodimentsshowing frame members 502 are depicted in FIG. 41A-E. Of course, otherconfigurations such as diamonds or other rounded or polygonal shapes canbe used. The diamond frame is a construct that takes a first form thatis smaller and expands to a larger frame. The diamond elements could beconstructed from a single wire or from multiple wires. Alternatively,the members could be constructed of elements that are moveable fixed ateach of the ends to allow expansion. A tether or attachment device 504is also depicted, which may be a suture, a wire, a screw, or otherattachment means known in the art.

The frame could be cut from a single material, such as flat stockNitinol to accomplish the same objective, as shown for example in FIG.31. Such shapes can be cut from flat stock using known methods, forexample, laser cutting. A heat forming step could also be employed, asknown in the art, to form barbs 132 in a shape that passes out of theflat plane of the stock material, as shown in FIG. 27 for example.

Another frame configuration, also not shown, is that of a spiral orcoil. The “Coil” design can be, for example, a spring steel or otherbiocompatible material that is wrapped to a first “wound” smallerconfiguration and expands to a larger unwrapped, unwound configuration.

Depending on the size of the openings in the frames described above,each of these concepts may or may not have a covering over them in orderto assure that the nucleus does not re-extrude from the intervertebraldisc space after placement of the device, as well as to serve assubstrate for the surrounding tissue to naturally incorporate thedevice. Coverings might include ePTFE, polyester, silicone, or otherbiocompatible materials. Coverings could also include natural materialssuch as collagen, cellulose, autograft, xenograft, allograft or similarmaterials. The covering could also be biodegradable in nature, such aspolyvinyl lactic acid.

Frames that are not covered may be permeable, such as a patch that isporous and allow for normal movement of fluids and nutrients through thepatch into and out of the annular ring while maintaining nucleusfragments larger than the porosity of the stent/patch within thesubannular space. Depending on the material that the frame isconstructed, a surface finish may be added to promote tissue ingrowthinto the patch. For example, a titanium sputtering of the device mayallow it to be more easily incorporated within the disc space.Alternatively, a NiTi or tantalum foam could be added to the outersurface of the patch to promote tissue ingrowth.

It is understood that there can be a variety of device designs ofpatches to accomplish the expansion of a device from a firstconfiguration, to a second configuration to occupy the sub-annular spaceand reduce re-extrusion of the nucleus. The following device conceptsare further discussed for additional embodiments of a device and/orsystem for the repair of an intervertebral disc annulus.

As mentioned hereinabove, the stent/patch according to the presentinvention may comprise a mass of fascial autograft, and that autograftmay be contained in a covering of material to form what will be referredto herein as a “bag”. Of course, this term is used not necessarily toconnote a five-sided closed container so much as to denote the notion offlexibly surrounding the volume of a patch/stent material so that it canbe manipulated in space.

In the most simplistic form, a prefabricated device of sutures could beused to form the “sling” to hold the fascial implant as discussed above.The advantage of this design over simple placement of sutures to holdthe autograft is better containment and control of the autograft duringand after implantation. The “sling” or a “bag” surrounds the fascialautograft to hold it in place. It is contemplated that other materials,such as a polyester mesh, could be used instead of the fascialautograft.

FIG. 38 shows an example of a prefabricated sling 300. There are threesutures used in this example, 302, 304, and 306, although there could bemore or less sutures as would be understood by one of ordinary skill inthe art. A collar member 308 has apertures or other features forattaching to the sutures. In this example, the third suture 306 passesalong or within the collar 308 to form a loop extending from the lateralextent of the collar 308. The first and second sutures 302, 304 formloops from the superior and inferior extents of the collar 308.Intersections 310 can secure the loops to each other with small loops orknots in the sutures, small fabric attachment pieces, or by smallpreformed devices resembling grommets placed on the suture to aid insecurement. Other knot tying techniques known in the art can also beemployed. Turning to FIG. 39, the collar is depicted within thesubannular space where the loops surround a fascial autograft 314 whichby pulling proximally the sutures 302, 304, 306 the graft is collapsedinto contact with the annular wall in a sealing manner. The sutures canbe made of known materials, e.g., biodegradable, bioabsorbable orbioresorbable Vicryl or biocompatible nylon. The collar can be made of afabric material, e.g., polyester. During placement, one end of some oreach suture can be passed through the inferior wall of the annulus andthe other end can be passed through the superior wall surrounding theaperture. After the placement of the sling into the wall of the annulus,the fascial autograft is placed within the sling. The sutures aretightened to bring the tissues together and also to help reappoximatethe aperture, as the collar size will be selected based on the surgeon'sjudgment according to the degree of reapproximation desired.

Other constructions can also be used to accomplish the same objective,such as a “bag” 404 formed of expandable PTFE as shown in FIG. 40. Thebag is placed through an aperture in the annulus 402. Additionally, aone way seal 406 can be positioned behind the aperture 408. Suturingtechniques for introducing cardiac valves could be employed to place theseal. It is understood that there could be multiple constructs toaccomplish the same objective and this is only given as an example.

There are a variety of ways to affix the device to the subannular wallof the annulus in addition to those discussed hereinabove. The followingexemplary embodiments are introduced here to provide inventiveillustrations of the types of techniques that can be employed to reducethe time and skill required to affix the patch to the annulus, versussuturing and tying a knot. Discussed hereinabove is the use of sutures,staples and other fixation devices, such as those passed through slot 18to affix the patch to the annulus as shown in FIG. 1. FIG. 20 alsodepicts the use of “barbs” on the surface of the stent to facilitatefixation to the annulus. In a simple example, as shown in FIG. 20, apatch/stent could be compressed, passed through a guide tube such astubes 18, 18A shown in FIGS. 22 and 23, and expanded within thesub-annular space. As shown in FIG. 42, the expanded patch 602 is shownhaving barbs 604, along with detachable delivery tool 608 and guide tube606. Once expanded, barbs 604 on the outer surface of patch 602 can beused to fix the patch into the inner wall 610 of the annulus 612 bypulling the patch back proximally, into the sub-annular wall 610, andpushing forward distally on the guide tube 606, thus driving the barbs604 into the annulus and drawing the inner and outer tissues of theannulus together and reapproximating the disc on either side of theaperture, as shown in FIG. 43. After the placement of the patch, thedelivery tool and guide tube are removed.

The advantage of this design described above is that it requires verylittle time and skill to place and secure the patch to the annulus whilealso drawing the tissues together.

Materials of the patch could be similar to materials discussedhereinabove. Anchoring barbs could be made of a biocompatible material,for example a metallic material (e.g., NiTi alloy, Stainless steel,Titanium), or a polymeric material (e.g., polypropylene, polyethylene,polyurethane). Anchoring barbs could also be abiodegradable/bioabsorbable material, such as a polyglycolic acid (PGA),a polylevolactic acid (PPLA), a polydioxanone (PDA) or for example aracemic polylactic acid (PDLLA). If the barbs included abiodegradable/bioabsorbable material, it is anticipated that the barbsmight have sufficient holding strength for a sufficient period of timeto allow the patch to be incorporated into the annulus during thehealing process. The advantage of having the anchoring barb of FIGS. 42and 43 being biodegradable/bioabsorbable is that after the incorporationof the patch into the annulus there may be no need for the barbs toprovide fixation. However, barbs pointing toward the outer surface ofthe annulus could pose a long term risk of penetration out of theannulus due to migration, and potentially impinging on the nerve rootand spinal canal. Biodegradable/bioabsorbable barbs address andadvantageously reduce any long-term risk in this regard.

It is also possible that the barbs could be made of both a biocompatiblecomponent and a biodegradable/bioabsorbable component. For example, thevery tip of the barb could be made of a biodegradable material. The barbcould penetrate the annulus wall with a rather sharp point, but afterdegradation the point of the barb would become dull. In this embodiment,the point would no longer induce continued scar formation after thepatch has been incorporated, nor pose a risk of penetrating out of theannulus onto the nerve root.

Another fixation means includes the passing of “anchoring bands” intothe wall of the annulus, vertebral bodies (superior, inferior, or both),or the Sharpey's Fibers (collagenous fibers between the junction of theannular fibers and vertebral bodies). In the following example ofanchors, the barbs or bands are affixed to the annulus/vertebralbodies/Sharpey's fibers. Another element, for example a suture, cinchline, or a staple is utilized to attach the anchor bands to the patch,and thus hold the patch in proximity to the inner wall of the annulus.In addition, these bands may re-approximate the tissues at the aperture.

Revisiting one example of using barbs to anchor the device is shown inFIG. 9, described hereinabove. Barbs or bone anchor screws 50 ands 52are passed into the superior and inferior vertebral bodies 54 and 56,respectively. Superiorly, suture 40 is passed through the outer wall ofthe annulus, to the sub-annular space. The suture is then passed throughthe eyelet 53 of bone anchor 52 and then passed through the wall of theannulus from the sub-annular space to the outer wall of the annulus. Theinferior end of the suture is similarly passed through the annulus,eyelet of the bone anchor, and back through the wall of the annulus.Both ends of suture 40 are tightened and tied. The advantage of thisconcept is that it allows for fixation of the device to a surface thatis known to be present in all discectomy procedures—the vertebralbodies. Whereas, it is possible, depending on the location and size of anatural rent that there may not be sufficient annulus accessible tofixate the device directly to the annulus. In addition to providing alocation for fixation, anchoring into the vertebral bodies may provide amore stable anchor surface.

Another example of fixating the device to inner wall of the annulus isshown in FIG. 29, and is further illustrated by FIGS. 44-47. Asdiscussed hereinabove, with reference to FIGS. 22-30, a patch 120 isplaced with a delivery tool 122, through the inner lumen of a guide tube118, into the sub-annular space and then expanded. This step can also beseen in FIGS. 45 and 46, where a patch 702 is folded and passed througha guide tube 706 and is held by a delivery tool 704. Also shown is aanchor band or staple 709 and an anchor band delivery device 708. Withinthe guide tube, or within the delivery tool, there is a suture line orcinch line 710 that is attached to the center of the patch 702. This canbe seen in FIG. 44 a with the guide tube 706 removed. As seen in FIGS.45C and 46A, the guide tube 706 is retracted after the patch 702 hasbeen expanded and deployed. Next, as shown in FIGS. 44 and 46, an anchorband delivery tool 708 is used to deliver one or more “bands” 709 ontothe outer surface of the annulus. These are intended to be anchored intothe wall of the annulus with barb shapes that do not allow for the barbsto be pulled back through the annulus. The anchor bands resemble aconstruction of a “staple”. The bands could actually be constructed byconnecting two barbed elements with, for example, a suture between thetwo barbed elements. The barbs and the connection band between the barbscould be constructed of the same material or of different materials. Forexample, the barbed part of the anchor band could be abiodegradable/bioabsorbable material (such as polyglycolic acid) orcould be constructed of a metallic or polymeric biocompatible material(e.g., titanium, NiTi alloy, stainless steel, polyurethane,polypropylene). In addition, the band that connects these barbs can beconstructed of materials that are similar to the barbs, or differentmaterials. For example, the connection band could be abiodegradable/bioabsorbable suture, such as Vicryl, or a biocompatiblematerial such as polypropylene. In addition, it is possible that theseelements are constructed from multiple materials to accomplish theobjective of anchoring into the annulus and providing for a fixationsite to draw the tissues together.

FIGS. 44B and 44C show the placement of the anchor bands 709 into theannulus 712 with the anchor band delivery tool 708. FIGS. 46A and 46Bschematically show the placement of the anchor bands 709 into the wallof the annulus 712 and the retraction of the anchor band delivery device708, with the patch delivery tool 704 still in place. FIG. 44D depicts arepresentative anchor band 709, having a pair of stainless steel barbs709″ connected by a suture 709′. FIG. 44E shows the patch 702, anchorbands 709, and cinch line or suture 710 with the delivery tools removed,prior to drawing the patch and the tissues of the annulus together. Inthis embodiment there is a pre-fabricated knot 714 on the cinch line,which is described further in FIG. 47B, although other knots arepossible. FIG. 47 a also shows a posterior view of the patching of theannulus with this device with knot 714. In this stent/patch 702 a pairof loops of 7 mm suture 709 are shown, which engage the cinch line andslip knot. These suture loops connect to the barbs directly, as in FIG.44, or loop to surgical staples, or are placed directly into theannulus. The presence of a pre-fabricated knot on the cinch line makesthe process of repairing quicker since there is no need to tie a knot.It also facilitates drawing the tissues together. The use of the cinchline and a pre-fabricated knot can be placed by, for example, anexternal tube such as a knot pusher. FIG. 44E is similar to the FIG. 29described hereinabove prior to “tying” the knot 145. FIG. 44F shows thedrawing of the patch and the annular tissues together by pulling on thesuture in the direction “A” indicated by the arrow. In this case, theKnot Pusher has been removed from the cinch line 710. The suture 710 isdrawn proximally to draw the patch 702 into engagement with the innerwall of the annulus to seal the aperture from within, as well as drawthe walls of the annulus together to reapproximate the annular aperture.FIG. 46C and FIG. 44G show the cinch line suture 710 tied and drawingthe annular tissues together, after the excess suture line has been cut.It is also apparent from this device, fixation and delivery system thatthe outer surfaces of the aperture are also drawn together forre-approximation.

The cinching of the anchor bands and the patch also allows for taking-upthe slack that allows for the accommodation of varying sizes. Forexample, the thickness of the annular wall surrounding the aperture canvary from 1 mm up to 10 mm. Therefore, if the anchor bands have a setlength, this design with a cinch line accommodates different dimensionsof the thickness of the wall of the annulus by drawing the “slack” ofthe bands together within the aperture.

Although it has been described here as patch placement that involves twolateral anchor bands with a suture to draw the patch, bands and tissuestogether, one or two or more bands could be used and two bands is onlyan example. Furthermore, the anchor bands were placed with the barbs ina superior-inferior fashion. One skilled in the art would recognize thatthese could be placed at different locations surrounding the aperture.Moreover, although it was described that the bands are placed into theannulus, these anchor bands could also be placed in the vertebral bodiesas shown in FIG. 48A generally at 800, or the Sharpey's Fibers 802, asshown in FIG. 48B generally at 804, adequately allowing for placement ofbarbs into adequate tissue.

Although the patch depicted in the example above does not have barbsattached to the patch, it is also possible to have the barbs asdescribed hereinabove to further promote the fixation of the patch tothe inner wall of the annulus.

Finally, although the drawings depict an aperture that lends itself tore-approximating the tissues, it is conceivable that some apertures,whether natural or surgically made, may be relatively large andtherefore might require the placement of additional material within theaperture to act as a scaffold for tissue in growth, between the patch onthe inner wall of the annulus and the anchor bands located on the outerwall. An example of material to fill the aperture might includeautograft para-spinal fascial tissue, xenograft, allograft, or othernatural collagenous materials. The filler material could also be of abiocompatible material such as a Dacron material. FIG. 51 shows theillustrative filling of an aperture with implant material 716 prior tocinching the suture 710.

As an alternative embodiment of the present invention, the anchor bands709 as described previously (anchor bands into annulus) could besufficiently long enough to pass through the annulus and then throughthe patch. The barbs in this embodiment have an engaging involvementwith the patch. This concept was previously discussed hereinabove inconnection with FIG. 30. Further illustration of such a system isschematically shown in FIGS. 49 and 50. Passing the barbs through thepatch, in this embodiment, provides additional security and safety byreducing the possibility that the barbs may migrate after implantation.In this application of the invention, the suture cinch line may (FIG.50) or may not (FIG. 30) be used in addition to the anchor bands to drawthe tissues together and reduce tissue movement surrounding theaperture.

In addition, although the bands shown in FIGS. 49 and 50 take the formof a “barb”, they could as easily take a form of a simple T-barb 720, asshown in FIG. 52E, or a C-type element wherein the object is to haveirrevocable engagement with the patch device 702 after the penetrationthrough the patch. A T-type attachment, when aligned longitudinally withthe suture, passes through the patch. The T section then rotates toprevent the suture anchor from being pulled back through the patch. Inanother embodiment a “C’ retainer made of a superelastic material may beattached to the end of the suture band. The C retainer is loaded into aneedle wherein it is held straight. The needle is used to pass the Cretainer and suture through the patch and deploy the retainer in asecond configuration in the shape of a “C”.

It is also foreseen within the scope of the invention that there may bepatch designs which will accommodate the placement and securement of theanchor to the fabric that covers the frame of the patch. For example, aframe for a patch that is made out of metal such as Nitinol can providefor “windows”. The device, covered with a mesh fabric, for examplesilicone or Dacron, would therefore allow the anchoring barbs to bepassed through the “windows” in the frame of the patch. In this case,the barb can be secured to the patch in the fabric covering the frame.

Alternatively, the patch can be secured by passing barbs that engage thelattice of the patch frame. These embodiments of the inventionillustrate designs in which the barbs engage with the vertical,horizontal or crisscrossed structures/members of the frame. In thiscase, the barbs would pass through the mesh or lattice of the frame andthey would be unable to pass back out of the structure.

Although this discussion refers to “anchor bands” that are shown to betwo anchors connected by a suture, it is also contemplated that singlebarbs with sutures are placed and the sutures' ends, at the outersurface of the annulus, are tied after placement through the patch. Itis also possible that these “single anchors” could be retained by asuture “pledget” on the outer wall of the annulus to better hold theouter surface, or could include a suture (or band) locking device.

One objective in the designs discussed hereinabove is to provide a wayto “pull up the slack” in a system to adjust the length of sutures andfor anchor bands. According to the present invention, a techniquereferred to as the “Lasso Cinch Knot” was developed as a means to drawthe anchor bands together with a suture cinch line that is incorporatedinto the patch design. FIG. 53 gives further description of the use ofthe Lasso embodiment. In essence, patch and frame constructs are usedthat incorporate the “barbs through the patch” design. Once the barbshave passed through the patch, an internal lasso 722 is drawn tightaround the sutures of the anchor bands and thus draws the extra suturematerial within the patch. The internal lasso gathers the sutures of thebands, and as the lasso is tightened, it cinches together the sutures ofthe bands and therefore tightens them and eliminates slack, bringing thepatch/stent into closer or tighter engagement with the annulus wall. Thepatch in FIG. 53 additionally provides for a diamond shape grid pattern,which advantageously provides a grid which will while allowing a probeor similar instrument to pass through with little resistance, providesresistance to a barb or other restraining feature on the instrument. Theframe shown can be made from nitinol, and the locking and holdingwindows shown at the center of the figure would allow for rotation aboutthe z-axis during placement. A slipknot technique using, for example aknot pusher, would aid in the loop pulling process by the lasso. Theinternal loop (lasso) can be tacked to the outside corners of thepatch/stent, in order to hold the loop at the outer edges of the patchframe. When cinching the lasso knot, the loop can be pulled free fromsome or all of its tacked attachment points to the frame, to preventdeformation of the planar shape of the frame when cinching the lasso. Asabove, the frame can be a composite structure or sandwich formed withsome type of mesh fabric. The proximal mesh fabric can be bonded fullyto the patch frame, for example through the use of an adhesive, forinstance a silicone. Adhesive, advantageously, can fill the intersticesof the grid pattern while allowing for easy probe penetration andprotection of the suture lines. Protection of the suture lines isadvantageous when the lasso is used to pull and bunch a group of bandsutures together.

It is also contemplated within the scope of the present invention thatsutures 710′ can be preattached directly to a stent/patch. As shown inFIG. 52A several separate barbs 709′″ into the annulus 712 can bedirectly attached to the patch 702. Each “barb” of FIG. 52A can beindependently placed into the annulus after the patch is deployed. Thiscan be seen to be similar to the embodiment including barbs 709″″ ofFIG. 55.

An alternative embodiment for securing a patch 902 and reapproximating arent or incision is to provide each of the separate barbs with sutureshaving variable lengths as shown in FIG. 56. Each independent suturebarb 904 is placed into the annulus 906 or into the patch 902 with thebarb delivery tool 908. After the placement, all of the suture lines 910are drawn taught, by drawing on the free ends that exit the patchdelivery tool 912. A locking element (which may be referred to as alocking clamp, or band locking device, or band retention device) 914that uses a gasket 916 and threading mechanism is attached to the patch902 and is used to tighten the gasket 916 around the distal ends of thesutures 910. The patch delivery tool 912 is removed and the extra suturelength is cut. It is also possible that the gasket mechanism could be apress-fit to accommodate the tightening of the sutures to the patch.

Alternatively, the locking mechanism can be as shown in FIG. 57,although in this case the engagement of the locking element 914′ takespart on barb 916. Pulling the suture 910 in the direction of arrow Bwill tighten and lockingly hold in tension to aid in securing andreapproximating the annulus. The adjustable length suture band betweenthe two anchors allows slack to be taken up between the anchors 916. TwoT-type anchors are shown in this example, but multiple anchors ofdiffering configurations could be used. The locking features can beincluded on the suture band, as depicted here, and allow forsubstantially one-way locking engagement with the anchor members. Thisadjustability advantageously promotes for the accommodation of varyingthickness of the annulus from patient to patient. The suture slack inthis embodiment may be taken up to close the defect in the annulusand/or to shorten the band between anchors for a secondary cinching ofmultiple tensioned suture bands as described hereinabove.

The cinch line and the Lasso concepts in essence try to facilitate there-approximation and drawing of tissues together in a fast and simpleway. Other contemplated embodiments for “tension” elements include usingan elastic coupler as a part of the anchor band used to fixate thedevice. The elastic coupler can be expanded for placement, and uponrelease, can draw tension to pull the tissues together. The couplercould be made of a biocompatible metal or polymer, or could beconstructed of a biodegradable/bioabsorbable material.

Similarly, an alternative embodiment to cause tension within the deviceand draw the tissues together after placement of the anchor bands mightinclude an elastic band or band with a spring which one end can beattached to the anchor bands and the other end attached to the patch.Alternatively, the anchor bands might, in and of themselves may be madeof an elastic band between the barbs, or may contain a spring elementbetween the barbs. Such an embodiment can be made to resemble aso-called “Bobber Spring.” Again, it is contemplated that the elastic orresilient element could be made from a wide variety of metals,polymeric, or biodegradable/bioabsorbable material.

FIG. 59 describes an embodiment where the patch element 1002 takes theform of a mesh seal. The securement is effected by a hook having a barbelement 1004 that penetrates the inner surface of the annulus 1006,while the inner connection of the hook (barb) 1004 is attached to thepatch in such a fashion as to add tension between the outer surface ofthe annulus and the inner surface in proximity to the patch, thusdrawing the annular tissues together. The patch/stent 1002 contains aspring ribbon element 1008 which can be formed from nitinol or otherspring material. Hooks 1010 are then deployed to “grab” the annulus,either through penetration or through grasping into the aperture 1012 asshown.

FIGS. 54 a-f shows another embodiment of a means to draw the suturelines together to cause tension between the inner and outer tissues ofthe annulus. Anchor bands, for example T-barbs 720′ are placed throughthe annulus and the patch, and they are secured to the patch 702.“Slack” in the suture of the anchor band is “rotated” around adetachable portion of the delivery tool 704′ and a locking element, forexample a screw configuration 724 as shown in the drawing, is used tolock the extra suture line in place affixed to threads 726 with thepatch 702. The delivery tool 704′ is then removed.

FIG. 58 shows alternative embodiments for tightening “anchoring barbs”with different configurations of sutures and cinch lines. For example inFIG. 58B each independent barb has a looped suture attached to it.Through each of these loops is passed a cinch line, which contains aknot. After placement of the barbs within the annulus, and possiblythrough the patch, the cinch line draws the loops of the barbs together.The advantage of this embodiment is that it allows for the independentplacement of multiple barbs and the ability to draw all of themtogether.

Although cinch lines have been described as using a knot to “lock” thelength of the suture, other mechanisms could also lock the band lockingdevice, as shown in FIG. 57. The locking of the suture length isaccomplished through a mechanical element located on the barb whichengages with three dimensional elements attached to the suture linewhich mechanically press fit through the engagement element on the barb,thus locking the length of the suture line into place.

Although the embodiments of FIG. 57 and FIG. 58 depict the use of asingle locking mechanism (e.g., knot on cinch line), it is conceivablethat various designs could use more than one locking element to achievethe re-approximation and drawing together the tissue surrounding anaperture.

All patents referred to or cited herein are incorporated by reference intheir entirety to the extent they are not inconsistent with the explicitteachings of this specification, including; U.S. Pat. No. 5,108,438(Stone), U.S. Pat. No. 5,258,043 (Stone), U.S. Pat. No. 4,904,260 (Rayet al.), U.S. Pat. No. 5,964,807 (Gan et al.), U.S. Pat. No. 5,849,331(Ducheyne et al.), U.S. Pat. No. 5,122,154 (Rhodes), U.S. Pat. No.5,204,106 (Schepers at al.), U.S. Pat. No. 5,888,220 (Felt et al.) andU.S. Pat. No. 5,376,120 (Sarver et al.).

Various materials know to those skilled in the art can be employed inpracticing the present invention. By means of example only, the bodyportions of the stent could be made of NiTi alloy, plastics includingpolypropylene and polyethylene, stainless steel and other biocompatiblemetals, chromium cobalt alloy, or collagen. Webbing materials caninclude silicone, collagen, ePTFE, DACRON, polyester, polypropylene,polyethylene, and other biocompatible materials and can be woven ornon-woven. Membranes might be fashioned of silicone, propylene,polyester, SURLYN, PEBAX, polyethylene, polyurethane or otherbiocompatible materials. Inflation fluids for membranes can includegases, liquids, foams, emulsions, and can be or contain bioactivematerials and can also be for mechanical, biochemical and medicinalpurposes. The stent body, webbing and/or membrane can be drug eluting orbioabsorbable, as known in the medical implant arts.

The foregoing discussion relates to the use of a patch (or stent). Insome clinical instances, the method of the invention may be accomplishedwithout the use of a patch, however. Moreover, a patch may beunnecessary to repair small apertures or apertures of certain shapes, orcertain weakened or thin portion(s) of an annulus. The inventiontherefore also encompasses methods for repairing or reconstructingannular tissue that do not necessarily involve the use of a patch, andto fixation devices and tools useful in carrying out these methods.

A comparatively simple embodiment of this method is shown in FIG. 7. Inthis embodiment, an annulus may be repaired or reconstructed by use ofsurgical sutures 40. One or more surgical sutures 40 may be placed atsuitable (e.g., about equal) distances along the sides of an aperture 44(or along the boundaries of thin or weakened regions) in the annulus 42.Any suitable surgical needle or its functional equivalent may be used toplace the suture. In cases where thinned or weakened regions of theannulus wall are in need of repair or reconstruction, it may beadvantageous to place a surgical incision in the affected region tocreate an aperture prior to proceeding with the method. Reapproximationor closure of the aperture 44 may be accomplished by tying the sutures40 so that the sides of the aperture 44 (or boundaries of a thin orweakened region) are drawn together. Without wishing to be bound bytheory, it is believed that the reapproximation or closure of theaperture 44 enhances the natural healing and subsequent reconstructionby the natural tissue (e.g., fibroblasts) crossing the now surgicallynarrowed gap in the annulus 42. Preferably, the surgical sutures 40 arebiodegradable, but permanent non-biodegradable sutures may be utilized.

The use of sutures alone may be insufficient. Accordingly, the presentinvention also provides additional fixation devices that may be used toreapproximate and hold annular tissue. Such fixation devices, asdescribed above, may contain an anchor portion and a band portion. Theanchor portion serves to fix the fixation device in the annular tissue.The band portion, attached to the anchor portion, serves toreapproximate annular tissue when tightened and secured. At least onefixation device is placed into, or though, the wall of an annulus in aportion surrounding the aperture (or in a boundary region surrounding athin or weakened portion of the annulus). The device is then drawn intension to pull together, wholly or partially, the surrounding annulartissue.

The anchor portion and bands are as described above, and preferably(though not necessarily) shaped to enter the annular tissue relativelyeasily and to resist removal. Examples of suitable anchor devicesinclude but are not limited to barbs, T-anchors, or combinationsthereof. FIG. 44 d depicts an exemplary anchor device containing barbs.

The band and the barbs may be separate elements or comprise onecontinuous element. Bands and barbs may be made of the same or differentmaterials.

The bands may be string-like, made from suture or similar material, orof any construction or dimension that is amenable to the delivery andengagement of the fixation device. For example, the band may have awidth greater than, in some embodiments far greater than, its thickness.The suture material may in some embodiments have a width:height ratio of1.25:1. In some embodiments, bands may be constructed, wholly orpartially, of a mesh tube. Moreover, different segments along the lengthof the band may have different dimensions and constructions. Forexample, the band may be constructed of thin material, such as nickeltitanium alloy or stainless steel wire, close to the anchor barbs, whilethe middle portion that spans the aperture may comprise a much widerband made of optionally softer material.

As described above, the fixation materials may be biocompatible orreabsorbable, or both. Examples of biocompatible or reabsorbablematerials for use, e.g., in band and/or barb (or anchor), include, butare not limited to, polylactic acid, polyglycolic acid, silk suture,polyethylene, stainless steel, polypropylene, nickel titanium alloy,polyester and their functional equivalents. Advantageously, the very tipof the barb could be made of biodegradable material. The barb may beconstructed of a material having a shape sufficiently sharp to penetratethe annulus wall, but sufficiently susceptible to wear to dull uponinsertion.

As an example of the foregoing, the embodiment depicted in FIG. 29 maybe adapted for use without patch 120. In this embodiment, barbs 134 and136 are plunged (inserted) into the annulus fibrosus from the exteriorof the annulus. Band 144 resides on the outer surface of the annulus andconnects barbs 134 and 136. When knot 145 is tightened or cinched withtether 142 and band 144, the tissues surrounding the aperture, the innerwall of the annulus, and the outer wall of the annulus, are drawntogether. Similarly, the arrangement shown in FIG. 30 may be modified bydeletion of the patch 120. Anchoring barbs 148 and 150, attached to band144, may be cinched, pulling the appropriate tissues together.

The function of the fixation devices of FIGS. 29 and 30 are similar toanchor bands 709 shown in FIGS. 44 c-44 e and 46 a-46 c. In each ofthese embodiments, the fixation device spans the aperture and is used todraw together the tissues surrounding the aperture, the inner surface ofthe annulus, and the outer surface of the annulus. Thus, in certainclinical situations, such as in the repair of a small aperture, it ispossible that a patch may be unnecessary and that cinching the fixationdevices may be sufficient to close the aperture.

FIGS. 57 a-c, 58 a-c, 60, 61 a, 61 b, 62 a-d, and 63 show additionalexamples of embodiments of the invention for annular repair orreconstruction without the use of a patch. For instance, in FIGS. 57a-c, in lieu of (or optionally in addition to) a patch, two anchors 916are shown having been passed through the annulus to the subannularspace. By drawing on band 910, the inner and outer walls of the annulusare drawn together in tension, which reapproximates the tissuesurrounding the aperture. FIG. 57 c shows a single anchor band acrossthe opening in the annulus. Multiple anchor bands may also be placedalong an incision or tear in the annulus.

The fixation devices of the invention could be delivered as a pair ofbarbs attached by a single band, as shown in FIG. 44 d, or each barbcould be delivered individually. Alternatively, multiple barbs may bepre-attached to single or multiple bands for ease and speed of delivery.For example, FIG. 60 shows a fixation device that has multiple anchors916 (or barbs, not shown) connected together in a configuration similarto FIGS. 58 b and 58 c, with each anchor 916 being deliveredindividually into, or through, the nucleus of the annulus 712. Theanchors 910, if present, may be shown as in the Figure. By drawing onthe cinch line, the tissues surrounding the aperture, the inner wall ofthe annulus, and the outer wall of the annulus are drawn together. Theknot of FIG. 60 can be similar to the knot shown in FIG. 47 b. Othertypes of knots, such as the knot shown in FIG. 7, may be used, however.Although knots are shown to affix the suture lines together, other meansto lock, fasten, clip, retain, or secure the sutures together may alsobe used. For example, FIG. 56 a shows an alternative way to lockindividual bands with barbs together with locking mechanism.

FIG. 56 a also shows an alternative embodiment of the fixation devicewhich is contemplated wherein multiple anchor barbs 904 are placedindividually with each anchor barb having a single band 910 that aredrawn together with other barbs and bands.

As previously mentioned, the present invention also encompasses deliverydevices of the following description. The delivery devices of thepresent invention are configured to deliver at least one fixation deviceinto (or through) the annulus or other surface or tissue. The deliverydevice will typically comprise a device or shaft having proximal anddistal ends.

The shaft of the device may be of any convenient length, typically from,e.g., 1 inch to 10 inches.

Materials of which to make the device include, but are not limited to:metals, such as stainless steel, nickel, titanium alloy, and titanium;plastics, such as PTFE, polypropylene, PEEK, polyethylene, andpolyurethane.

Advantageously, the shaft of the device will have a cross-sectionalshape suitable to accommodate an ejection rod and at least one fixationdevice. In one embodiment, at least a portion of the shaft of the devicemay be hollow, having a circular, elliptical, triangular, trapezoidal orother suitable cross-sectional area sufficient to accommodate anejection rod, described below.

The delivery device may also contain a handle or raised surfaceconfigured to accommodate the shape of surgeon's hands or fingers foreasier handling. Such raised or configured portion may be made of thesame or different material as the tube or shaft. Suitable materialsinclude polymers, such as acrylic polymers, polyurethane; and metals,such as stainless steel and titanium.

The delivery device may be configured to accommodate and deploy at leastone fixation device, such as a barb or T-anchor with one or moreassociated bands. Advantageously, the distal end of the delivery devicewill comprise a hollow needle or cannula 711, having a circular,elliptical, triangular, hexagonal or other inner cross sectional area,suitable to accommodate the cross-sectional shape of the fixation devicewithin. The distal point of the cannula 711 is advantageously sharpened,as a needle, to accommodate insertion. The cannula 711 is advantageouslycut obliquely as shown in FIG. 63 to form a sharp leading surface orpoint for ease of insertion. The cannula 711 may contain a cut or groovealong its side to accommodate one or more anchors 709 as shown (orbarbs, not shown), e.g., in FIGS. 61 b or 63. In one embodiment, the atleast one fixation device (including band and barb or T-anchor) isdisposed within the cannula 711 as shown in FIGS. 61 a, 61 b, and/or 63.Alternatively, the T-anchor 709 (or barb, not shown), or other fixationdevice may be hollow and disposed in a manner surrounding the device ofthe delivery device.

The delivery device 708 will also advantageously contain within it anejection rod 715. The proximal end of the ejection rod 715 typicallywill contain an end portion 713 to function as a stopper, e.g., having adiameter larger than the remaining portion of the rod, such as is shownin FIG. 61 a. The diameter of the remaining portion of the ejection rod715 will be small enough for insertion within the shaft of the device708. Upon insertion of the cannula 711 into the location of choice, theejection rod is pushed to deliver the fixation device. The deliverydevice is then removed.

Advantageously, the ejection rod 715 and delivery device may beconfigured to deliver multiple fixation devices, sequentially orsimultaneously. Thus, if multiple fixation devices are contained withinthe device, the ejection rod 715 and delivery device may be configuredsuch that the rod 715 be pushed a first distance, sufficient to delivera first fixation device. The device is then removed from the firstinsertion point and inserted into a second insertion point, where theejection rod is then pushed a second distance for delivery of a secondfixation device, and so-on as desired. For simultaneous delivery ofmultiple fixation devices, multiple delivery devices may be arranged inparallel (or substantially parallel). The distance between (or among)the delivery devices may be fixed or adjustable, as desired.

The distance the ejection rod 715 is pushed to define a first, second,and subsequent distances may be regulated by feel. Alternatively, thedistance can be regulated by the architecture of the device. Forexample, the shaft and ejection rod may be fitted with anotch-and-groove configuration, respectively. In such configuration, thenotch in the outer surface of the ejection rod may be aligned with agroove in the inner surface of the device. The length of the groovedefines a first distance. The ejection rod 715 would be then turned orrotated within the device, aligning the notch within the device to asecond groove defining a second distance, and so-on. In an alternativeembodiment, the ejection rod and anchor portion of the fixation device(e.g., barb or T-anchor) may surround the shaft of the device, as asleeve surrounds an arm. In such a configuration, the delivery devicewould comprise a solid shaft and the ejection rod and fixation devicewould be at least partially hollow and disposed over the distal portionof the delivery device. Pushing the ejection rod in a proximal to distaldirection would deploy the anchor portion of the fixation device.

FIGS. 61 a and 61 b describe one embodiment of an anchor band deliverydevice 708 and fixation means. FIG. 61 a shows a general drawing of adelivery device. FIG. 61 b further depicts the distal end of thedelivery device. Anchor band delivery device 708 contains two pointedneedles or cannulas 711. Each cannula 711 contains an anchoring T-typeanchor 709 (or barb) positioned within the distal end of the cannula711. A band 709′ links the two anchors 709 (or barbs) together and acinch knot 714 secures the anchors (or barbs). Cinch line 710 is pulledto decrease the length of the band 709′ that attaches the anchors 709.

Referring to FIG. 62 a, anchor band delivery device 708 is inserted intothe annulus 712 sufficiently to engage the inner layers of the annulus712, and preferably located at the inner wall of the annulus 712. Theanchors 709 are ejected from the delivery device by pressing theejection rod 715 in a fashion to expel the T-anchors 709 (or barbs, notshown) from the device. For example, pressing on the proximal end ofejection rod 715 as shown in FIG. 61 a drives the ejection rod 715 in adistal direction, thus expelling the anchor from the device. FIG. 62 bshows the anchors 709 (or barbs) after being ejected. FIG. 62 c shows aknot pusher 716 attached to the device that can be used to tighten theknot 714 once the fixation device is secured into the annular tissue.FIG. 62 c shows the placement of two anchors 709, or fixation devices(anchors and bands), after they have been delivered to the annulus andbefore the bands 709 have been tightened. The knot pushers 716 of bothdevices are still in contact with the knots and the delivery needleshave been pulled back, away from the annulus. FIG. 62 d shows the finalplacement of the two anchor bands after drawing together the tissuessurrounding the aperture 717, the inner wall of the annulus 712, and theouter wall of the annulus; and, after tightening and cutting the knotlocated on each anchor band.

Although this drawing shows the passage of the bands superior andinferior to the aperture, these bands could also be placed in amultitude of locations to effect desired or equivalent outcomes.

In addition, as previously described, one could use barbs having amultitude of configurations. One could also configure delivery devicesto deliver one (as in FIG. 63), two (as in FIG. 61 a), or more barbssimultaneously, and according to predetermined or variable distances orpatterns. The delivery devices may also be configured to eject one, two,or more barbs sequentially. Further, the barbs could be delivered by adelivery device that does not require a cannula to cover the barb. Insuch a configuration, the barb may be disposed on the tip or outside ofthe delivery device's shaft, and removed therefrom upon injection intothe desired location of the annulus or other tissue. Bands and knots maybe pre-tied to accommodate each configuration, as previously discussed.

For example, although FIGS. 61 and 62 a-b depict a device that placestwo anchors 709 banded together with one device, one could accomplish anequivalent or other desired result with a single device that deliversmultiple barbs at the same time, as shown in FIGS. 44 b and 44 c.

FIG. 63 shows an alternative delivery device that delivers two or moreanchors (or barbs) from a single cannula 711. In this embodiment, afirst single anchor 709 is ejected from the cannula 711 by pushing theejection rod 715 a first distance sufficient to eject the first anchor709, but insufficient to eject the second. Then the delivery device isremoved from the first site and passed into another annular location.The second anchor (or barb), not shown, connected to the first anchor orbarb by band, is ejected out of the cannula 711 by pushing the ejectionrod 715 an additional distance sufficient to eject the second anchor (orbarb) into a second fixation point in the annulus.

Although much of this description has described placement of the anchorsinto the annulus (or soft tissue) of the disc, one could performanchoring into other tissues surrounding the aperture, including thebone or sharpey fibers as previously described in FIGS. 48 a and 48 b,it is also contemplated that, given the delivery device construction, abone drill or similar device may be necessary to facilitate theplacement of the delivery device through the bony or similar tissue.

The band 709′ connecting the thus implanted anchors (or barbs)advantageously contains a moveable knot 714 between the anchors.Suitable knots include, but are not limited to, the Roeder knot and itsfunctional equivalents, and are advantageously, but not necessarily,pre-tied. After insertion of both anchors 709 (or barbs), the band 709′is advantageously tightened by hand or by pushing on the knot with aknot-pusher or similar device. Although not shown in FIG. 63, the knotpusher may be integral to the delivery device. After drawing togetherthe tissues surrounding the aperture, inner wall, and outer wall of theannulus, the excess suture line can be cut. It is also possible to use acutting device integral to the delivery device to cut the band aftercinching. Although the device shown in FIG. 63 depicts two anchors beingdelivered from a single device, multiple anchors or barbs could bedelivered from the same or a similar type of device. FIG. 60 shows adelivered configuration of fixation means that may result from the useof a single device to deliver multiple anchors sequentially.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1. A method for repairing intervertebral disc tissue, comprising:inserting a first anchor member having a first elongate element attachedthereto into disc tissue in proximity of a defect to be repaired;inserting a second anchor member having a second elongate elementattached thereto into the disc tissue in proximity of the defect to berepaired and in a different location opposite the defect from the firstanchor; providing an adjustable coupling between the second elongateelement of the second anchor member to the first elongate element of thefirst anchor member; and applying tension to at least one of the firstand second elongate elements such that the tension is applied to thetissue around the defect to be repaired to reapproximate the defect. 2.The method of claim 1, wherein the tissue to be repaired is annulusfibrosus of the intervertebral disc.
 3. The method of claim 1, whereinthe first and second elongate elements are slidably coupled to eachother.
 4. The method of claim 3, wherein the first and second elongateelements are slidably coupled to each other by a third elongate elementextending there between.
 5. The method of claim 4, further comprising: aone slip knot formed on at least one of the first, second, and thirdelongate elements, the slip knot maintaining the first and secondelongate elements in a fixed position with respect to each other.
 6. Themethod of claim 4, wherein the first, second, and third elongateelements are each formed in a loop, the loop of the first elongateelement being attached to the first anchor member, and the loop of thesecond elongate element being attached to the second anchor member, andwherein the loop of the third elongate element is connected to the loopsof the first and second elongate elements.
 7. The method of claim 6,wherein at least one of the loops includes a slip knot, and wherein thestep of tensioning includes pulling a terminal end of at least one ofthe loops which includes the slip knot to adjust a size of the at leastone loop.
 8. The method of claim 1, wherein the first elongate elementis formed in a loop and is coupled to the first anchor member, and thesecond elongate element is formed in a loop and is coupled to the secondanchor member, and wherein the loop of the first elongate element iscoupled to the loop of the second elongate element.
 9. The method ofclaim 1, wherein the first and second elongate elements are fixedlyattached to the first and second anchor members, respectively.
 10. Themethod of claim 1, wherein the first and second elongate elements arecoupled to each other by a third elongate element.
 11. The method ofclaim 10, wherein the third elongate element is formed in a loop. 12.The method of claim 11, wherein the loop of the third elongate elementincludes a slip knot.
 13. The method of claim 12, wherein the loop ofthe third elongate element is selectively adjustable.
 14. The method ofclaim 1, wherein the first elongate element of the first anchor memberis formed in a loop.
 15. The method of claim 14, wherein the secondelongate element of the second anchor member is formed in a loop.